[HOTFIX][Streaming] Handle port collisions in flume polling test

This is failing my tests in #1777. @tdas

Author: Andrew Or <andrewor14@gmail.com>

Closes #1803 from andrewor14/fix-flaky-streaming-test and squashes the following commits:

ea11a03 [Andrew Or] Catch all exceptions caused by BindExceptions
54a0ca0 [Andrew Or] Merge branch 'master' of github.com:apache/spark into fix-flaky-streaming-test
664095c [Andrew Or] Tone down bind exception message
af3ddc9 [Andrew Or] Handle port collisions in flume polling test
SPARK-2882: Spark build now checks local maven cache for dependencies

Fixes [SPARK-2882](https://issues.apache.org/jira/browse/SPARK-2882)

Author: Gregory Owen <greowen@gmail.com>

Closes #1818 from GregOwen/spark-2882 and squashes the following commits:

294446d [Gregory Owen] SPARK-2882: Spark build now checks local maven cache for dependencies
[SPARK-2583] ConnectionManager error reporting

This patch modifies the ConnectionManager so that error messages are sent in reply when uncaught exceptions occur during message processing.  This prevents message senders from hanging while waiting for an acknowledgment if the remote message processing failed.

This is an updated version of sarutak's PR, #1490.  The main change is to use Futures / Promises to signal errors.

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>
Author: Josh Rosen <joshrosen@apache.org>

Closes #1758 from JoshRosen/connection-manager-fixes and squashes the following commits:

68620cb [Josh Rosen] Fix test in BlockFetcherIteratorSuite:
83673de [Josh Rosen] Error ACKs should trigger IOExceptions, so catch only those exceptions in the test.
b8bb4d4 [Josh Rosen] Fix manager.id vs managerServer.id typo that broke security tests.
659521f [Josh Rosen] Include previous exception when throwing new one
a2f745c [Josh Rosen] Remove sendMessageReliablySync; callers can wait themselves.
c01c450 [Josh Rosen] Return Try[Message] from sendMessageReliablySync.
f1cd1bb [Josh Rosen] Clean up @sarutak's PR #1490 for [SPARK-2583]: ConnectionManager error reporting
7399c6b [Josh Rosen] Merge remote-tracking branch 'origin/pr/1490' into connection-manager-fixes
ee91bb7 [Kousuke Saruta] Modified BufferMessage.scala to keep the spark code style
9dfd0d8 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-2583
e7d9aa6 [Kousuke Saruta] rebase to master
326a17f [Kousuke Saruta] Add test cases to ConnectionManagerSuite.scala for SPARK-2583
2a18d6b [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-2583
22d7ebd [Kousuke Saruta] Add test cases to BlockManagerSuite for SPARK-2583
e579302 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-2583
281589c [Kousuke Saruta] Add a test case to BlockFetcherIteratorSuite.scala for fetching block from remote from successfully
0654128 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-2583
ffaa83d [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-2583
12d3de8 [Kousuke Saruta] Added BlockFetcherIteratorSuite.scala
4117b8f [Kousuke Saruta] Modified ConnectionManager to be alble to handle error during processing message
717c9c3 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-2583
6635467 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-2583
e2b8c4a [Kousuke Saruta] Modify to propagete error using ConnectionManager
SPARK-2879 [BUILD] Use HTTPS to access Maven Central and other repos

Maven Central has just now enabled HTTPS access for everyone to Maven Central (http://central.sonatype.org/articles/2014/Aug/03/https-support-launching-now/) This is timely, as a reminder of how easily an attacker can slip malicious code into a build that's downloading artifacts over HTTP (http://blog.ontoillogical.com/blog/2014/07/28/how-to-take-over-any-java-developer/).

In the meantime, it looks like the Spring repo also now supports HTTPS, so can be used this way too.

I propose to use HTTPS to access these repos.

Author: Sean Owen <srowen@gmail.com>

Closes #1805 from srowen/SPARK-2879 and squashes the following commits:

7043a8e [Sean Owen] Use HTTPS for Maven Central libs and plugins; use id 'central' to override parent properly; use HTTPS for Spring repo
HOTFIX: Support custom Java 7 location
[SPARK-2887] fix bug of countApproxDistinct() when have more than one partition

fix bug of countApproxDistinct() when have more than one partition

Author: Davies Liu <davies.liu@gmail.com>

Closes #1812 from davies/approx and squashes the following commits:

bf757ce [Davies Liu] fix bug of countApproxDistinct() when have more than one partition